Roofing granule and method of coloring same



Patented .liuiy l2, lhdd ROUFHNG GRFlNULiE AND METHOD Uh Clllfillr URINE: SAME of Illinois No Drawing. Application October 3, 1935, Serial No. Q3388 3 Claims.

This invention relates to composition. roofing, and, more particularly, to colored granules for use on roofing material and the process of coloring the granules.

cement or binder. More or less difiiculty has been experienced in the use of artificially colored granules because of the tendency of the cement to chip, crack, dissolve or to be otherwise affected by the weather. The present invention seeks to such as slate, quartz, shale, traprock and the like.

The solid constituent of the binder employed is preferably in the form of a powder which with dried by heating to a temperature above 400 F. and below 800 F., preferably between 450 and 600 F., and simultaneously agitated to prevent agglomeration.

The following formula of material for color- 5 One of the objects of the invention is the prothe addition of phosphoric acid accompanied by 5 vision of new and improved roofing granules a moderate amount of heat will form a cement having novel means for cementing the color pigfor attaching the color pigment firmly to the merit to the surfaces of the granules. surface of the granules. For convenience of: de-

A further object of the invention is the proviscription, this powdered material will be resion of a new and improved method of coloring ferred to asbinder powder. 0 granules for use on composition roofing. The binder powder may be made from com- A further object of the invention is the propounds of one or more of the common metals of vision of a new and improved method of attachgroups III, IV, VII and VIII of the periodic ing color pigment to roofing granules without classification of the elements which are capable of damaging the granules or injuring the color or forming sesquioxides. The compounds of these luster oi the color pigment. metals most suitable are the oxides, hydroxides A still further object of the invention is the or carbonates thereof. Any compounds of these provision of a new and improved colored granule elements capable of forming a. phosphate with that is inexpensive to manufacture, which is durphosphoric acid may be used, as, for instance, the able and one in which the color pigment is firmly oxide or hydroxide of aluminum, titanium and secured. cobalt; and the oxide, carbonate or hydroxide oi Other and further objects and advantages of manganese, iron and nickel.

the invention will appear as the description The material for the binder powder is reduced proceeds: to powder form in any suitable manner, as in a In 'the manufacture of composition rooting, it ball mill, and it is then ready for use. In coloris common practice to impregnate strips of fling the granules, the binder powder, color pigbrous material with a bituminous composition ment and granules may all be mixed together, or and then by a suitable binder of weather rethe color pigment and binder powder be first sisting material secure granules to the surface mixed together in dry form and then mixed with of the strips. These granules may be of natural ,the granules. The granules are preferably first color-that is, they may be made from stone, slate moistened, after which the mass of binder powor the like having a natural color of the desired der and color pigment are mixed together. After hue. In other instances, the granules are artithe mass is thoroughly mixed, an aqueous soluficially colored, the color pigment being attached tion of phosphoric acid is applied to form a to the surface of the granules by a suitable cement coat on the granules and the whole mass eliminate these difficulties by the provision of s each n f granules green gives satisfactory a weather resisting cement for securing color results and is here given by Way of example pigment to the surface of the granules. ER-- It has also been proposed to fuse the binder Pounds onto the granules but the heat required to fuse Phosphoric acid 5 certain binder materials is such as to materially Oxide of one of the metals named here affect the luster of certain pigments and is such in in a Sumclent quaflfity to chemical as to prohibit the use altogether of certain other react on substantially all the @1195" pigments phone acid, as, for instance, if alumi- In the present invention a moderate amount of Hum (A1203) is; used, 9 10 to 15 heat is employedpbut not suiiiciently high to Chrome omde (gram c0101 plgment) injuriously affect the color pigments employed. 18

Ifhe granules to be colored are reduced and The exact compositions of the reaction prod; screened to the proper size in the usual manner. nets of the acid and powdered material are not definitely known, and, consequently, I do not They may be made from any suitable material,

desire to be bound by any statements of theory relative thereto. It is probable that during the heating operation, for instance, some of the phosphates may be converted into pyro-phosphate. It is also likely that in some of the reactions forming the ultimate product, basic or oxy-phosphates may also be formed. The term phosphate is therefore intended to include the reaction products of phosphoric acid and the binder powder.

Preferably, though not necessarily, the cement is applied in a thin coat. It has also been found by experiment that the application of heat, as outlined above, gives good results. This may be done in a rotary kiln which will also agitate the mass to prevent agglomeration.

The insoluble silicates of any of the above enumerated metals and of any of, the metals of Group II that unite with silica, such as aluminum silicate, iron silicate, calcium silicate, slate dust and the like may also be used with satisfactory results. In preparing the silicate, the same is reduced to powder form in a ball or hammer mill after which it is mixed with the pigment which has also previously been reduced to powder form, as described above. The phosphoric acid is then added and the mixture heated and simultaneously agitated as in the foregoing examples.

It is understood that the compounds herein specified are by way of example only, and that the claims are not to be limited except by the prior art.

I claim as my invention:

1. A method of coloring granules of mineral matter for use on composition roofing which comprises attaching color pigment to the surface of the granules with a thin layer of weatherproof cement, comprising the reaction product of substantially 40 lbs. of phosphoric acid of 75% strength with from to pounds of a compound of one of the common metals of Groups III, IV, VII and VIII of the Periodic Classification of the Elements which is capable of forming a sesquioxide for each ton of granules, heating the mass between 450 F. and 600 F. and simultaneously agitating the mass to prevent agglomeration.

2. A method of coloring granules of mineral matter selected from the group. consisting of slate, quartz, shale and. traprock for use on composition rooflng which comprises attaching color pigment to the surface of the granules with a thin layer of weather-proof cement comprising the reaction product of phosphoric acid with a compound of one of the common metals of Groups III, IV, VII and VIII of the Periodic Classification of the Elements which is capable of forming a sesquioxide, heating the mass between 400 F. and 800 F. and simultaneously agitating the mass to prevent agglomeration.

3. A colored granule for use on composition roofing comprising a body of mineral matter selected from the group consisting of "slate, quartz, shale and traprock and a color pigment attached to the surface of said body by a thin layer of weather-proof cement comprising the reaction product of heating between 400 F. and 800 F. phosphoric acid with a compound of one of the common metals of Groups III, IV, VII and VIII of the Periodic Classification of the Elements which is capable of forming a sesquioxide.

HENRY R. GUNDLACH. 

